Is there a custom character creator addon in Blender?
In addition to the already mentioned MakeHuman (which actually started as a Blender Add-on but is now a standalone application) there is also Manuel Bastioni Lab.

It is a Blender Addon that allows parameter driven custom character creator directly inside the Blender viewport, in a similar vein to MakeHuman.

It can create realistic human figures as well as fantasy or anime themed characters.